Dalton's Atomic theory is a scientifictheory about atoms. Dalton made the theory to explain why elements would combine in certain ways[1] The idea of atoms was already known at the time, but not widely accepted. Dalton's theory of atoms was based on actual observation. Before this, ideas about atoms were based more on philosophy.

His theory stated that:

Everything is made from atoms

Nothing can be simpler than an atom

Atoms can not be made or destroyed

Chemical reactions are made when atoms are moved around, put with other atoms or taken away from a group of other atoms

Atoms of the same element are the same, because they have the same mass

Atoms can only be joined in special ratios

Although not a part of the Dalton's original atomic theory, it is believed that Dalton's atomic theory contained the way that the atoms use to bond together.